300 research outputs found

    The mechanism of improving the knock-out properties of moulding sands with water glass

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    Abstract The article concerns a trial of explaining the mechanism of improving the knock-out properties of moulding sands with water glass made in ester technology after using the new additive called Glassex. Within the labour, the variety of technological and basic researches were done, including the researches evaluating the chemical influence of the new additive

    Plasma density profile reconstruction of a gas cell for Ionization Induced Laser Wakefield Acceleration

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    Laser-driven plasma wakefields can provide hundreds of MeV electron beam in mm-range distances potentially shrinking the dimension of the actual particle accelerators. The plasma density plays a fundamental role in the control and stability of the acceleration process, which is a key development for the future electron injector proposed by EuPRAXIA. A gas cell was designed by LPGP and LIDYL teams, with variable length and backing pressure, to confine the gas and tailor the gas density profile before the arrival of the laser. This cell was used during an experimental campaign with the multi TW-class laser at the Lund Laser Centre. Ionization assisted injection in a tailored density profile is used to tune the electron beam properties. During the experiment, we filled the gas cell with hydrogen mixed with different concentration of nitrogen. We also varied the backing pressure of the gas and the geometrical length of the gas cell. We used a transverse probe to acquire shadowgraphic images of the plasma and to measure the plasma electron density. Methods and results of the analysis with comparisons between shadowgraphic and interferometric images will be discussed

    Constraints on Charon's Orbital Elements from the Double Stellar Occultation of 2008 June 22

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    The original publication is available at http://iopscience.iop.org/1538-3881/International audiencePluto and its main satellite, Charon, occulted the same star on 2008 June 22. This event was observed from Australia and La Réunion Island, providing the east and north Charon Plutocentric offset in the sky plane (J2000): X= + 12,070.5 ± 4 km (+ 546.2 ± 0.2 mas), Y= + 4,576.3 ± 24 km (+ 207.1 ± 1.1 mas) at 19:20:33.82 UT on Earth, corresponding to JD 2454640.129964 at Pluto. This yields Charon's true longitude L= 153.483 ± 0fdg071 in the satellite orbital plane (counted from the ascending node on J2000 mean equator) and orbital radius r= 19,564 ± 14 km at that time. We compare this position to that predicted by (1) the orbital solution of Tholen & Buie (the "TB97" solution), (2) the PLU017 Charon ephemeris, and (3) the solution of Tholen et al. (the "T08" solution). We conclude that (1) our result rules out solution TB97, (2) our position agrees with PLU017, with differences of ΔL= + 0.073 ± 0fdg071 in longitude, and Δr= + 0.6 ± 14 km in radius, and (3) while the difference with the T08 ephemeris amounts to only ΔL= 0.033 ± 0fdg071 in longitude, it exhibits a significant radial discrepancy of Δr= 61.3 ± 14 km. We discuss this difference in terms of a possible image scale relative error of 3.35 × 10-3in the 2002-2003 Hubble Space Telescope images upon which the T08 solution is mostly based. Rescaling the T08 Charon semi-major axis, a = 19, 570.45 km, to the TB97 value, a = 19636 km, all other orbital elements remaining the same ("T08/TB97" solution), we reconcile our position with the re-scaled solution by better than 12 km (or 0.55 mas) for Charon's position in its orbital plane, thus making T08/TB97 our preferred solution

    Free Radicals, Salicylic Acid and Mycotoxins in Asparagus After Inoculation with Fusarium proliferatum and F. oxysporum

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    Electron paramagnetic resonance was used to monitor free radicals and paramagnetic species like Fe, Mn, Cu generation, stability and status in Asparagus officinalis infected by common pathogens Fusarium proliferatum and F. oxysporum. Occurrence of F. proliferatum and F. oxysporum, level of free radicals and other paramagnetic species, as well as salicylic acid and mycotoxins content in roots and stems of seedlings were estimated on the second and fourth week after inoculation. In the first term free and total salicylic acid contents were related to free radicals level in stem (P = 0.010 and P = 0.033, respectively). Concentration of Fe3+ ions in porphyrin complexes (g = 2.3, g = 2.9) was related to the species of pathogen. There was no significant difference between Mn2+ concentrations in stem samples; however, the level of free radicals in samples inoculated with F. proliferatum was significantly higher when compared to F. oxysporum

    Functional features of gene expression profiles differentiating gastrointestinal stromal tumours according to KIT mutations and expression

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    <p>Abstract</p> <p>Background</p> <p>Gastrointestinal stromal tumours (GISTs) represent a heterogeneous group of tumours of mesenchymal origin characterized by gain-of-function mutations in <it>KIT </it>or <it>PDGFRA </it>of the type III receptor tyrosine kinase family. Although mutations in either receptor are thought to drive an early oncogenic event through similar pathways, two previous studies reported the mutation-specific gene expression profiles. However, their further conclusions were rather discordant. To clarify the molecular characteristics of differentially expressed genes according to GIST receptor mutations, we combined microarray-based analysis with detailed functional annotations.</p> <p>Methods</p> <p>Total RNA was isolated from 29 frozen gastric GISTs and processed for hybridization on GENECHIP<sup>® </sup>HG-U133 Plus 2.0 microarrays (Affymetrix). <it>KIT </it>and <it>PDGFRA </it>were analyzed by sequencing, while related mRNA levels were analyzed by quantitative RT-PCR.</p> <p>Results</p> <p>Fifteen and eleven tumours possessed mutations in <it>KIT </it>and <it>PDGFRA</it>, respectively; no mutation was found in three tumours. Gene expression analysis identified no discriminative profiles associated with clinical or pathological parameters, even though expression of hundreds of genes differentiated tumour receptor mutation and expression status. Functional features of genes differentially expressed between the two groups of GISTs suggested alterations in angiogenesis and G-protein-related and calcium signalling.</p> <p>Conclusion</p> <p>Our study has identified novel molecular elements likely to be involved in receptor-dependent GIST development and allowed confirmation of previously published results. These elements may be potential therapeutic targets and novel markers of <it>KIT </it>mutation status.</p

    Human Umbilical Cord Blood Treatment in a Mouse Model of ALS: Optimization of Cell Dose

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    Amyotrophic Lateral Sclerosis (ALS) is a multicausal disease characterized by motor neuron degeneration in the spinal cord and brain. Cell therapy may be a promising new treatment for this devastating disorder. We recently showed that a single low dose (10(6) cells) of mononuclear human umbilical cord blood (MNC hUCB) cells administered intravenously to G93A mice delayed symptom progression and modestly prolonged lifespan. The aim of this pre-clinical translation study is to optimize the dose of MNC hUCB cells to retard disease progression in G93A mice. Three different doses of MNC hUCB cells, 10x10(6), 25x10(6) and 50x10(6), were administered intravenously into pre-symptomatic G93A mice. Motor function tests and various assays to determine cell effects were performed on these mice.Our results showed that a cell dose of 25x10(6) cells significantly increased lifespan of mice by 20-25% and delayed disease progression by 15%. The most beneficial effect on decreasing pro-inflammatory cytokines in the brain and spinal cord was found in this group of mice. Human Th2 cytokines were found in plasma of mice receiving 25x10(6) cells, although prevalent human Th1 cytokines were indicated in mice with 50x10(6) cells. High response of splenic cells to mitogen (PHA) was indicated in mice receiving 25x10(6) (mainly) and 10x10(6) cells. Significantly increased lymphocytes and decreased neutrophils in the peripheral blood were found only in animals receiving 25x10(6) cells. Stable reduction in microglia density in both cervical and lumbar spinal cords was also noted in mice administered with 25x10(6) cells.These results demonstrate that treatment for ALS with an appropriate dose of MNC hUCB cells may provide a neuroprotective effect for motor neurons through active involvement of these cells in modulating the host immune inflammatory system response

    Comprehensive mutation analysis of 17 Y-chromosomal short tandem repeat polymorphisms included in the AmpFlSTR® Yfiler® PCR amplification kit

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    The Y-chromosomal short tandem repeat (Y-STR) polymorphisms included in the AmpFlSTR® Yfiler® polymerase chain reaction amplification kit have become widely used for forensic and evolutionary applications where a reliable knowledge on mutation properties is necessary for correct data interpretation. Therefore, we investigated the 17 Yfiler Y-STRs in 1,730–1,764 DNA-confirmed father–son pairs per locus and found 84 sequence-confirmed mutations among the 29,792 meiotic transfers covered. Of the 84 mutations, 83 (98.8%) were single-repeat changes and one (1.2%) was a double-repeat change (ratio, 1:0.01), as well as 43 (51.2%) were repeat gains and 41 (48.8%) repeat losses (ratio, 1:0.95). Medians from Bayesian estimation of locus-specific mutation rates ranged from 0.0003 for DYS448 to 0.0074 for DYS458, with a median rate across all 17 Y-STRs of 0.0025. The mean age (at the time of son’s birth) of fathers with mutations was with 34.40 (±11.63) years higher than that of fathers without ones at 30.32 (±10.22) years, a difference that is highly statistically significant (p < 0.001). A Poisson-based modeling revealed that the Y-STR mutation rate increased with increasing father’s age on a statistically significant level (α = 0.0294, 2.5% quantile = 0.0001). From combining our data with those previously published, considering all together 135,212 meiotic events and 331 mutations, we conclude for the Yfiler Y-STRs that (1) none had a mutation rate of >1%, 12 had mutation rates of >0.1% and four of <0.1%, (2) single-repeat changes were strongly favored over multiple-repeat ones for all loci but 1 and (3) considerable variation existed among loci in the ratio of repeat gains versus losses. Our finding of three Y-STR mutations in one father–son pair (and two pairs with two mutations each) has consequences for determining the threshold of allelic differences to conclude exclusion constellations in future applications of Y-STRs in paternity testing and pedigree analyses

    Toward Male Individualization with Rapidly Mutating Y-Chromosomal Short Tandem Repeats

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    Neurocognition and quality of life after reinitiating antiretroviral therapy in children randomized to planned treatment interruption

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    Objective: Understanding the effects of antiretroviral treatment (ART) interruption on neurocognition and quality of life (QoL) are important for managing unplanned interruptions and planned interruptions in HIV cure research. Design: Children previously randomized to continuous (continuous ART, n=41) vs. planned treatment interruption (PTI, n=47) in the Pediatric European Network for Treatment of AIDS (PENTA) 11 study were enrolled. At study end, PTI children resumed ART. At 1 and 2 years following study end, children were assessed by the coding, symbol search and digit span subtests of Wechsler Intelligence Scale for Children (6-16 years old) or Wechsler Adult Intelligence Scale ( 6517 years old) and by Pediatrics QoL questionnaires for physical and psychological QoL. Transformed scaled scores for neurocognition and mean standardized scores for QoL were compared between arms by t-test and Mann-Whitney U test, respectively. Scores indicating clinical concern were compared (&lt;7 for neurocognition and &lt;70 for QoL tests). Results: Characteristics were similar between arms with a median age of 12.6 years, CD4 + of 830 cells/\u3bcl and HIV RNA of 1.7 log 10 copies/ml. The median cumulative ART exposure was 9.6 in continuous ART vs. 7.7 years in PTI (P=0.02). PTI children had a median of 12 months off ART and had resumed ART for 25.2 months at time of first assessment. Neurocognitive scores were similar between arms for all tests. Physical and psychological QoL scores were no different. About 40% had low neurocognitive and QoL scores indicating clinical concern. Conclusion: No differences in information processing speed, sustained attention, short-term memory and QoL functioning were observed between children previously randomized to continuous ART vs. PTI in the PENTA 11 trial
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